The present invention relates to a needle protection device or cap adapted for co-action with an hypodermic syringe that includes a container, a plunger which can be moved reciprocatingly in said container by means of a rod, and a needle which is fixed to or fastenable to one end-part of the container.
The needle protection device basically includes a tubular member, normally a tubular member of circular cross-section, whose axial length is slightly grater than the length of the needle.
More particularly, the present invention relates to a needle protection device that has an inner, radial-related cross-section which corresponds or at least essentially corresponds to the outer radial-related cross-section of the container.
This cross-section dimensioning of the needle protection device enables said device to be arranged for axial movement relative to the container, from a position in which the needle is covered by the device to a position in which said needle is exposed, or vice versa.
There has long been a desire to protect people who handle hypodermic syringes (either for injection and/or aspiration purposes) against accidental injury (prick-injuries), and several different designs of needle protectors have been proposed to this end.
These needle protectors are usually displaceably or removably mounted to the container of the syringe and are designed to cover the needle and the needle point.
The needle protector is removed prior to injection and/or aspiration, so as to expose the needle and its point.
For the sake of simplicity, the following description is concerned solely with the injection of liquids, although it will be understood that the concepts of the invention are equally as applicable to the aspiration of fluids.
A needle which remains exposed after an injection has been given can very well be contaminated and therewith transmit serious sicknesses to a person who is accidentally injured by the exposed needle and its point.
Various different types of needle protectors which protect people against accidental injury are known to the art. Such protectors basically include a tubular member that has a protective seal fitted on its free end.
A needle protector of this kind will have the form of a sleeve which can be readily removed from the syringe immediately prior to an injection. This sleeve must be kept separate during the injection process and replaced by hand over the needle upon completion of the injection, so as to shield the needle against unintentional contact therewith.
The sleeves, or tubular members, of this type of needle protector are dimensioned at their open part for secure but easily released co-action with the part of the needle attached to the container.
Other known needle protection constructions are movable over the container and co-act therewith during the injection, said syringe and said needle protecting means together forming a unit.
The present invention relates to this category of needle protection means.
Earlier known hypodermic syringe constructions that include needle protection means within this category have been described and illustrated in the following patent publications:
This publication teaches a needle protection device (19) which in a first position covers the needle (15) and the needle point (25), and in a second, upwardly moved position exposes the needle and the needle point.
The needle protection device (19) has the form of a tubular member that has at its free end a hole (41) which is large enough to allow a needle holding element (24) or a needle protection device (29) to pass through.
The hole (41) may be covered with a material that is split by the needle (15) and/or the needle protection device (29). The covering material functions as a sealing end-region of the tubular needle protection device and serves to seal the end-related edge or end surface of the tubular member.
This publication teaches a needle protection device (1) which can be moved reciprocatingly between fixed positions, i.e. between a needle covering position and a needle exposing position. The free end of the needle protection device (1) is conical and has a central opening which is adapted to embrace the needle attachment (4).
This publication teaches a needle protection device which includes an opening, i.e. a hole (58), and the free end (56) of the needle protection device (60) corresponds to the needle cross-section.
When taking into consideration the technical deliberations that a person skilled in this particular art must make in order to provide a solution to one or more technical problems that he/she encounters, it will be seen that on the one hand it is necessary initially to realise the measures and/or the sequence of measures that must be undertaken to this end, and on the other hand to realise which means is/are required to solve one or more of said problems. On this basis, it will be evident that the technical problems listed below are highly relevant to the development of the present invention.
In the case of a needle protection device which in a needle covering position co-acts with the container and which when moved over the container allows the point of the needle to penetrate through the bottom of said device, and which upon completion of an injection or some corresponding process can be moved to a needle protecting position, it will be seen when considering the present state of the art as described above that a problem resides in providing conditions with the aid of simple means that will enable a membrane which sealingly covers the cross-sectional area of the tubular member of said device to be placed in a position where it is well protected from externally acting forces.
It will also be seen that a technical problem resides in producing with simple means a needle protection device, in the form of a tubular member, that will enable a thin membrane to be placed in a well protected position.
It will also be seen that a technical problem resides in the provision of conditions, with simple means, which enable a thin, tough, membrane element to be formed within the tubular member at an adapted distance from the end-region of the needle protection device.
It will also be seen that a technical problem is one of providing conditions which enable a first end-part of the tubular member that lies distal from the membrane to be provided with a first part of a two-part coupling element active between the tubular member and the container and having the form of one or more inner radially-related and/or axially-related grooves.
Another technical problem is one of realising the significance of and the advantages afforded by providing a second part of said coupling element on the container in the form of a radially related and/or axially related edge, and to position said edge at or adjacent to said first end-part.
Another technical problem is one of realising the significance of and the advantages afforded by giving the material from which the tubular member is made and the dimensions of said tubular member, at least in the vicinity of said first end-part, properties that will allow the tubular member to expand over said edge as it is moved along the container.
It will also be seen that a further technical problem is one of realising the significance of and the advantages associated with positioning the membrane within the tubular member at an adapted distance from the end surface of said member and integrating the membrane with the tubular member in general.
Another technical problem is one of realising the significance of and the advantages associated with constructing the needle protection device in a manner which will enable the hypodermic needle to be bent whilst protected by said protection device, therewith to eliminate the risk of accidental damage by the needle and/or to render the needle unusable after having completed an injection.
The present invention takes as its starting point a needle protection device adapted for use with an hypodermic syringe which includes a container, a plunger that can be moved reciprocatingly in said container by means of a rod, and a needle which is fixed to or fastenable to one end-part of the container, said needle protection device having basically the form of a tubular member whose axial length is slightly greater than the length of the needle and which includes the features mentioned in the introduction in other respects.
With the intention of solving one or more of the aforesaid a technical problems, it is proposed in accordance with the invention that said tubular member shall include a thin membrane which covers the cross-sectional area of said member and which shall be placed at an adapted distance from the end-related edge or end-surface of the tubular member.
According to proposed embodiments that lie within the scope of the inventive concept, it is proposed that a first end-part of the tubular member lying distal from the membrane is provided with a first part of a two-part coupling element between the tubular member and the container.
According to one embodiment, this first part is comprised of an inner radially-related and/or axially-related groove.
According to another embodiment, a second coupling-part is comprised of a radially-related and/or axially-related edge, where said edge is positioned at or adjacent to said end-part.
It is particularly proposed that the material from which the tubular member is made and the dimensioning of said tubular member, at least in the vicinity of the first end-part, imparts to said member properties that will enable it to expand over said edge.
It is also proposed that a first end-part of the tubular member lying distal from the membrane is provided with two first coupling-parts included in a two-part coupling arrangement, where said two parts are axially displaced from one another.
It is also proposed that the membrane shall be protected by the tubular member, by placing said membrane within the tubular member at a small distance from the end surface of said member, and that said membrane has a ring-shaped edge.
Those advantages primarily obtained with a needle protection device adapted for a hypodermic syringe in accordance with the present invention reside in the provision of features which enable the needle protection device to be moved readily along the container of the syringe, said needle protection device being provided with a membrane which seals the cross-sectional area of the end-part that lies distal from the container and which ensures that the needle and point of said needle will be effectively covered by the protection device, and that when the protection device is moved along the container the point of the needle will penetrate the membrane and therewith expose the needle, and where upon completion of an injection or some corresponding process the needle protection device can be moved back to a needle covering position.
A particular advantage is that the membrane is protected against the effect of externally acting forces and is positioned within the tubular member at a distance from the end-related edge or end-surface of the tubular member, for example.
The primary characteristic features of a needle protection device adapted for an hypodermic syringe in accordance with the present invention are set forth in the characterising clause of the following claim 1.